No Such Thing as “Mission Impossible”
Cornerstone Prototype Development utilizes
SURFCAM to tackle its exotic workload
Jobs deemed impossible by other manufacturers are all in a day’s
work for Cornerstone Prototype Development, a fabrication
company that accomplishes what no one else can do.
For General Manager Craig Watkins, whose diverse duties include
engineering and programming, the only sure thing is that he’ll
never be sure what types of jobs are on the horizon.
“We do a lot of really exotic things that other shops don’t have the
knowledge or software, or ability, to do. Everything that we do is
About The Company:
Name: Cornerstone Prototype
Development
different — all of the time.”
Business: Full-service design,
engineering, CNC Machining, rapid
prototyping, metal fabrication
Watkins naturally took to engineering as a child and today has
nearly 20 years of experience in the manufacturing industry, seven
of them at the Pawtucket, Rhode Island-based Cornerstone.
Website: cornerstonepd.com
Established in 1996 and billed as a full-service design and
fabrication outfit, Cornerstone builds prototypes for virtually any
industry or product. Its mission is to “assist companies,
inventors and designers in bringing their ideas into tangible
concepts and functioning prototypes.”
“We typically sit down with clients to understand what they want to
accomplish and where they are so far,” Watkins says. “It’s easy to
make a rough prototype, but we want to create something with
manufacturability in mind. If something has an electrical
Benefits Achieved:
• Maximization of 3-axis machinery
• Dramatic reduction in programming
time for multi-holed thermoform
equipment
• Time saved with SURFCAM’s ability
to .STL files for verification
component, we want to make sure it’s capable of serving its
purpose.”
Comments:
The roster of prototyping services offered by Cornerstone includes
CNC machining, engineering, design, model-making, tooling, rapid
prototyping, RTV molding, urethane casting, painting, sculpture,
electronics and hair rooting. Hair-rooting services typically apply to
doll heads for the creation of characters for TV and film.
“We like the functionality and the
The company also offers a range of custom thermoforming
services, which include everything from 3-D design to tooling and
other production-related items. Most prototypes are produced in
metal, foams, plastics, glass and resins, and in quantities of
between one and 10.
Craig Watkins
General Manager
interface of SURFCAM. We stretch the
limits of the capabilities of 3-axis
machines and 3-axis software.”
To accomplish its wide range of exotic feats, Cornerstone uses a
selection of CNC machinery and the SURFCAM computer-aidedmanufacturing (CAM) solution by Vero Software.
“We like the functionality and the interface of SURFCAM,” Watkins
says. “We stretch the limits of the capabilities of 3-axis machines
and 3-axis software.”
Cornerstone’s staff of six includes two CNC programmers who are
able to program in up to four axes with a horizontal rotary table on
a 3-axis mill.
The company’s inventory of machinery includes a Makino V-33
vertical machining center, a high-precision 3-axis mill; a Leadwell V60 vertical machining center; several Milltronics VM-17 vertical
machining centers, one retrofitted with a fourth axis; a CNC
ProtoTRAK lathe; and a handful of ProtoTRAK mills. “SURFCAM
works well with anything,” Watkins says of Cornerstone’s ability to
use a single CAM solution throughout its shop.
For Watkins, getting down to the business of prototyping is both an
art and a science. He uses Adobe Illustrator®, a vector-graphics
program, and SOLIDWORKS® computer-aided-design (CAD)
software, by Dassault Systemes, for the design and engineering
portion of his job.
“We do a lot of work from photos,” Watkins says. “A lot of times, I’ll
take a photo, extract the edges and bring it into SOLIDWORKS to
create a solid model.” If Watkins generates a .dxf file in Illustrator,
that file can easily be imported into both SOLIDWORKS and
SURFCAM.
Many of Cornerstone’s jobs are consumer products, such as a
recent bird-feeder project that involved designing a feeder that
could be folded flat for ease in shipping.
Another job entailed the design and production of a full-scale
working model of a horse’s leg, complete with anatomically correct
muscles, joints and ligaments. Watkins and his team derived all
design information from a CAT scan provided by a veterinarian.
The purpose of the working horse model was to test an ankle brace
developed by Cornerstone’s customer. “The ligaments and tendons
were actually cables that hooked up to gauges and indicators, so if
the horse stepped down you could accurately tell how much 100
pounds of pressure, et cetera, would affected the ankle brace,”
Watkins explains.
The company has also designed and prototyped a display model for
wines, which “looked like a giant wine bottle with shelves in the
middle,” as well as a campaign for popular golf-products producer
Titleist.
While SURFCAM has simplified the overall process of the company’s
prototype work, Watkins cites a number of features that
significantly increase efficiency in both programming and
machining.
“We do a lot of thermoform tooling for the packaging industry, and
all of the tooling is vented with tiny holes of different depths,” he
explains.
To machine the thermoform production tool, Watkins drills a 1/4”
diameter hole on the backside of the tool within .030” of the
surface geometry. On the front side of the tool, a tiny drill — which
could not machine all the way through the material — is used to
create a smaller hole for evacuation.
“The 1/4” diameter holes end within .030” from the molds’ surface
geometry,” Watkins says. “SURFCAM puts a center line in every
single hole, and that center line can be used to determine depth,
which makes it a lot easier when we machine the smaller
evacuation holes on the flip side.
“Once the model is imported, I’m already programming and I don’t
have to tell it how deep to go,” he says. “If I couldn’t do that and I
had 100 holes, it would be 100 operations — but it becomes just
one operation.”
Watkins also saves programming time with SURFCAM’s ability to
use .STL files for verification. “From a programming point of view,
you can run tools one, two and three, and then save an .STL file for
each,” Watkins says. “If you cut a part and then want to make a
change, you want to go back and verify that it will work without
having to run a complete simulation of every operation.”
In other words, if Watkins wants to make a change only to the third
operation, he can skip simulating operations one and two and go
straight to the third tool that he wants to adjust. “It’s kind of like a
fast forward,” Watkins says. “We have parts that can take a while to
verify — though the efficiency of the toolpath helps a lot with
that.”